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For those outside of quantum research, academia and the tech savvy in the know, there are many misconceptions about what Quantum computing actually is, in layman’s terms it will give us the ability to achieve calculations far beyond the reach of any conventional classical supercomputer.

On that basis there are many that propose many game changing use cases such as developing new materials, because in theory it will be possible to simulate down to the atomic level. New cures or drugs to treat terminal and less serious diseases could be developed very quickly and much cheaper than they are today, (which for me is the most exciting use cases), or they could upend cryptography and security by cracking otherwise invincible codes. The later is the concern for many, last year I had dinner with one of the world’s top professors working on Quantum and he said calmly “Quantum is the atom bomb of the 21st century” however I was relieved to hear that achieving quantum supremacy is still some years away, hopefully by then we will have less hot headed and divisive leaders. One thing for sure is that as much as people saying that classical computing AI and cryptography changes the world, it will, but nothing will accelerate change faster than Quantum. Those in business who aren’t prepared for or at least understand how Quantum changes everything, in my opinion will crumble as they play catch up.

However although Quantum supremacy is years away, after decades of painstaking, gradual progress, researchers are finally close to building quantum computers powerful enough to do things that conventional classical computers cannot.
Google are amongst those across the world that have been doing lots of work towards this, while Intel and Microsoft also have significant quantum projects, there are well-funded startups including D-Wave, Rigetti Computing, IonQ, and Quantum Circuits and lets not forget that arguably the most likely scenario is that academia will get there first, with usaual suspects such as MIT, Stanford and Harvard, plus the likes of The University of Waterloo in Ontario, Canada, the University of Science & Technology of China in Hefei, Anhui, China and the University of Maryland in the US, The Russian Quantum Centre in Moscow are doing special things and in my opinion are more advanced than many others and one to watch.

So with many leading the charge, who gets there first?

At IBM’s Index Developer Conference held in San Francisco this week, the company showed off its latest prototype: a quantum computing rig housing 50 qubits, one of the most advanced machines currently in existence.

Some claim that nobody can match IBM’s pedigree in this area, 50 years ago, the company produced advances in materials science that laid the foundations for the computer revolution.

Charles Bennett has long led this charge he joined IBM in 1972, quantum physics was already half a century old, but computing still relied on classical physics and the mathematical theory of information that Claude Shannon had developed at MIT in the 1950s. It was Shannon who defined the quantity of information in terms of the number of “bits” (a term he popularised but did not coin) required to store it. Those bits, the 0s and 1s of binary code, are the basis of all conventional computing.

One year later, Bennett helped lay the foundation for a quantum information theory that would challenge all that. It relies on exploiting the behaviour of objects at the atomic scale. At that size, a particle can exist “superposed” in many states (e.g., many different positions) at once. Two particles can also exhibit “entanglement,” so that changing the state of one may instantaneously affect the other.

Bennett and others realised that some kinds of computations that are exponentially time consuming, or even impossible, could be efficiently performed with the help of quantum phenomena. A quantum computer would store information in quantum bits, or qubits. Qubits can exist in superpositions of 1 and 0, and entanglement and a trick called interference can be used to find the solution to a computation over an exponentially large number of states. It’s annoyingly hard to compare quantum and classical computers, but roughly speaking, a quantum computer with just a few hundred qubits would be able to perform more calculations simultaneously than there are atoms in the known universe.

Bennet has worked with many including Konrad Zuse, who developed the first programmable computer, and Richard Feynman, an important contributor to quantum theory. Feynman has raised the idea of computing using quantum effects commenting “The biggest boost quantum information theory got was from Feynman,‘Nature is quantum, goddamn it! So if we want to simulate it, we need a quantum computer”.

IBM’s quantum computer is one of the most promising in existence it has been designed to create and manipulate the essential element in a quantum computer: the qubits that store information.

The IBM machine exploits quantum phenomena that occur in superconducting materials. For instance, sometimes current will flow clockwise and counterclockwise at the same time. IBM’s computer uses superconducting circuits in which two distinct electromagnetic energy states make up a qubit.

The superconducting approach has key advantages. The hardware can be made using well–established manufacturing methods, and a conventional computer can be used to control the system. The qubits in a superconducting circuit are also easier to manipulate and less delicate than individual photons or ions.

Inside IBM’s quantum lab, engineers are working on a version of the computer with 50 qubits. You can run a simulation of a simple quantum computer on a normal computer, but at around 50 qubits it becomes nearly impossible. That means IBM is theoretically approaching the point where a quantum computer can solve problems a classical computer cannot: in other words, quantum supremacy.

But, quantum supremacy is an elusive concept. You would need all 50 qubits to work perfectly, when in reality quantum computers are beset by errors that need to be corrected for. It is also devilishly difficult to maintain qubits for any length of time; they tend to “decohere,” or lose their delicate quantum nature, much as a smoke ring breaks up at the slightest air current. And the more qubits, the harder both challenges become.

“If you had 50 or 100 qubits and they really worked well enough, and were fully error-corrected—you could do unfathomable calculations that can’t be replicated on any classical machine, now or ever,” says Robert Schoelkopf, a Yale professor and founder of a company called Quantum Circuits. “The flip side to quantum computing is that there are exponential ways for it to go wrong.”

Another reason for caution is that it isn’t obvious how useful even a perfectly functioning quantum computer would be. It doesn’t simply speed up any task you throw at it; in fact, for many calculations, it would actually be slower than classical machines. Only a handful of algorithms have so far been devised where a quantum computer would clearly have an edge. And even for those, that edge might be short-lived. The most famous quantum algorithm, developed by Peter Shor at MIT, is for finding the prime factors of an integer. Many common cryptographic schemes rely on the fact that this is hard for a conventional computer to do. But cryptography could adapt, creating new kinds of codes that don’t rely on factorisation.

This is why, even as they near the 50-qubit milestone, IBM’s own researchers are keen to dispel the hype around it. Jay Gambetta, IBM researcher said “We’re at this unique stage, We have this device that is more complicated than you can simulate on a classical computer, but it’s not yet controllable to the precision that you could do the algorithms you know how to do.”

What gives the IBM’s team hope is that even an imperfect quantum computer might still be a useful one.

Gambetta and other researchers have zeroed in on an application that Feynman envisioned back in 1981. Chemical reactions and the properties of materials are determined by the interactions between atoms and molecules. Those interactions are governed by quantum phenomena. A quantum computer can—at least in theory—model those in a way a conventional one cannot.

Last year, Gambetta and colleagues at IBM used a seven-qubit machine to simulate the precise structure of beryllium hydride. At just three atoms, it is the most complex molecule ever modelled with a quantum system. Ultimately, researchers might use quantum computers to design more efficient solar cells, more effective drugs, or catalysts that turn sunlight into clean fuels.

Those goals are a long way off. But, Gambetta says, it may be possible to get valuable results from an error-prone quantum machine paired with a classical computer.

“The thing driving the hype is the realisation that quantum computing is actually real,” says Isaac Chuang, a MIT professor. “It is no longer a physicist’s dream—it is an engineer’s nightmare.”

Chuang led the development of some of the earliest quantum computers, working at IBM in Almaden, California, during the late 1990s and early 2000s. Though he is no longer working on them, he thinks we are at the beginning of something very big—that quantum computing will eventually even play a role in artificial intelligence.

But he also suspects that the revolution will not really begin until a new generation of students and hackers get to play with practical machines. Quantum computers require not just different programming languages but a fundamentally different way of thinking about what programming is. As Gambetta puts it: “We don’t really know what the equivalent of ‘Hello, world’ is on a quantum computer.”

In 2016 IBM connected a small quantum computer to the cloud. Using a programming tool kit called QISKit, you can run simple programs on it; thousands of people, from academic researchers to students, have built QISKit programs that run basic quantum algorithms. Now Google and other companies are also putting their nascent quantum computers online. You can’t do much with them, but at least they give people outside the leading labs a taste of what may be coming.

The startup community is also getting excited, with many already proposing a business built on a technology so revolutionary that it barely exists.

This enthusiasm could sour if the first quantum computers are slow to find a practical use. The best guess from those who truly know the difficulties—people like Bennett and Chuang—is that the first useful machines are still several years away. And that’s assuming the problem of managing and manipulating a large collection of qubits won’t ultimately prove intractable.

Things are already speeding up, to see a recent article about how Quantum is already being used click here

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Source: MIT

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